Finding the Fourth Proportional to 1,398.17, 1,929.50 and 800.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.17 : 1,929.50 = 800.79 : x
2. Step 2: Convert to fraction form
   1,398.17/1,929.50 = 800.79/x
3. Step 3: Cross multiply
   1,398.17x = 1,929.50 × 800.79
4. Step 4: Simplify right side
   1,398.17x = 1,545,124.31
5. Step 5: Solve for x
   x = 1,545,124.31/1,398.17
6. Step 6: Final answer
   x = 1,105.10